United Graduate School of Agricultural Science and Veterinary Science, Gifu University, Gifu, Japan; Division of Virology and Medical Zoology, Chiba Prefectural Institute of Public Health, Chiba, Japan; Department of Virology 1, National Institute of Infectious Diseases, Tokyo, Japan.
Department of Virology 1, National Institute of Infectious Diseases, Tokyo, Japan.
Ticks Tick Borne Dis. 2019 Feb;10(2):344-351. doi: 10.1016/j.ttbdis.2018.11.010. Epub 2018 Nov 13.
Ehrlichiosis is a tick-borne bacterial disease caused by pathogens of the Ehrlichia genus. Although human ehrlichiosis has not been reported in Japan, Ehrlichia spp., which are closely related to Ehrlichia chaffeensis, were detected in several species of ixodid ticks. In this study, the presence of Ehrlichia spp. in ticks in Japan was studied by using isolation and molecular detection methods. In total, 1237 ticks were collected from vegetation in western, central, and eastern parts of Japan. The ticks were tested for detection of ehrlichial DNA with a nested polymerase chain reaction and/or isolation by inoculation of mice with the homogenate. Ehrlichial DNA was detected in 29 of these ticks. The ehrlichial DNAs, groEL and 16S rRNA genes, detected in Ixodes turdus showed a high similarity to those of E. chaffeensis with 94.7% and 99.2% identity, respectively. Ehrlichia sp. HF and Candidatus Neoehrlichia mikurensis were also detected in I. ovatus. Furthermore, Ehrlichia sp. HF was isolated from laboratory mice that were intraperitoneal inoculated with I. ovatus tick homogenate. Some ehrlichial agents detected in Ixodes ticks might be a previously unknown Ehrlichia species. In this study, Candidatus N. mikurensis was detected in I. ovatus ticks. Because I. ovatus is distributed widely and cases of its tick bite in humans are ubiquitously reported in Japan, there is a potential for ehrlichiosis to be endemic to Japan, necessitating intensive surveillance of this infectious disease.
埃立克体病是一种由埃立克体属病原体引起的蜱传细菌性疾病。尽管日本尚未报告人类埃立克体病，但在几种硬蜱中检测到与查菲埃立克体密切相关的埃立克体属病原体。在本研究中，采用分离和分子检测方法研究了日本蜱中的埃立克体属病原体。从日本西部、中部和东部的植被中采集了 1237 只蜱。用巢式聚合酶链反应和/或用匀浆接种小鼠进行分离，检测这些蜱中是否存在埃立克体 DNA。在其中 29 只蜱中检测到埃立克体 DNA。从 Ixodes turdus 中检测到的埃立克体 DNA、groEL 和 16S rRNA 基因与 E. chaffeensis 的同源性分别高达 94.7%和 99.2%。在 I. ovatus 中还检测到埃立希体 HF 和候选新立克次体。此外，从腹腔内接种 I. ovatus 蜱匀浆的实验室小鼠中分离到埃立希体 HF。从 Ixodes 蜱中检测到的一些埃立克体病原体可能是一种以前未知的埃立克体物种。在本研究中，在 I. ovatus 蜱中检测到候选新立克次体。由于 I. ovatus 分布广泛，在日本普遍报告有人被其叮咬的病例，因此埃立克体病在日本可能呈地方性流行，需要对这种传染病进行强化监测。
